JP5241331B2 - Digital broadcast receiver - Google Patents

Description

  The present invention relates to a digital broadcast receiving apparatus that realizes faster channel selection time and improved memory use efficiency.

  In conventional digital broadcast receivers, program specific information (Program Association Table; hereinafter referred to as PAT), program map table (hereinafter referred to as PMT), etc. PSI), acquisition of packet identifier (Packet Identifier; hereinafter referred to as PID) of video / audio basic stream information (Elementary Stream; hereinafter referred to as ES), acquisition of video and audio packets, etc. are the following sequential processes.

  (1) Upon entering the channel selection process, the PAT inserted in the transport stream (TS) output from the tuner is first acquired. (2) Obtain PMT PID corresponding to the service to be selected from PAT. (3) The PID of the video / audio ES is acquired from the PMT acquired using this PID. (4) First, format information (video resolution, aspect ratio, audio sampling frequency, etc.) is acquired from this ES. (5) Decoding is continued after acquisition, and mute is released when video / audio that can be output can be generated.

As described above, in the conventional channel selection processing, depending on the timing at which the channel selection information is acquired, it is necessary to wait for retransmission thereof, and the channel selection processing takes time.
For example, when a tuner acquires a packet, if the PMT is acquired before the PAT as shown in FIG. 1, the PMT is not used and it is necessary to wait until the next PMT is acquired. As a result, a delay occurs in the channel selection process. Therefore, a technique has been proposed in which a packet acquired by a tuner when selecting a channel is cached in a memory, and the PMT at that time is not wasted and the channel is selected at high speed (Patent Document 1).

JP 2004-31629 A

  In the above method, a large amount of information may be stored in a memory when performing a channel selection process, and it is necessary to mount a memory with a large capacity in advance. There is also a problem that it takes a lot of time to wait for PAT acquisition to start decoding.

  Therefore, the present invention provides a digital broadcast receiving apparatus that can reduce memory consumption and shorten the time required for channel selection processing.

  In order to solve the above-described problems, the present invention is a digital broadcast receiving apparatus, which is a data input means for inputting digital data including program specifying information, and the input digital data is divided and transferred in units of transport stream packets. Packet separation means, tuner stability investigation means for investigating the ratio of normal packets and damaged packets in the acquired transport stream packets, or time measurement means for measuring time for a certain period of time, and PID in the transport stream Stream configuration investigation means for examining each bit rate, stream cache memory for storing a specific transport stream packet obtained from the data input means, and which packet among the packets obtained from the data input means and when And the above stream key In a digital broadcast receiving apparatus having a stream control means for transferring to a cache memory or a decoder, an A / V decoder for decoding video information, and a mute control means for outputting decoded information to the user, immediately after the start of the channel selection process, When the tuner is unstable, the stream control means estimates the video packet identification number from the ratio and bit rate even if the information necessary for channel selection has not been acquired. In the configuration using the timer, the packet identification number is examined for a certain period, and the identification number of the video packet is estimated even if information necessary for channel selection is not acquired.

  Further, the stream control means determines when and which transport packets are stored and output, and suppresses memory consumption. The stream control means sends the video packet to the decoder even if the information necessary for channel selection is not acquired, and performs the decoding process in advance.

  By suppressing memory consumption necessary for speeding up the channel selection process, the capacity of the installed memory can be reduced. In addition, since the decoding process can be started in advance, the channel selection process can be speeded up.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 shows a block diagram of a digital broadcast receiving apparatus according to the first embodiment of the present invention. In the digital broadcast receiver according to the first embodiment of the present invention, the tuner / demodulator 100 and the packet separation means 101, the tuner stability investigation means 102, the stream configuration investigation means 103, the stream cache control means 104, the stream cache memory 105 An audio / video decoder 106 and a mute canceling means 107.

  The tuner / demodulator 100 demodulates a broadcast signal transmitted with an analog modulated wave into a TS. A TS is composed of one or more streams of video, audio, caption information, data broadcast, and the like. The TS is divided into TS packets of 188 bytes and transmitted. When demodulation is not performed correctly due to noise or the like, the bit of the “transport error indicator” in the TS packet header shown in FIG. 3 is set to true “1”.

  The packet separation means 101 separates the TS packet into information (PAT, PMT, etc.) necessary for channel selection, video / audio ES, etc. according to the PID value. The PAT of information necessary for channel selection is fixed at 0 as the PID value, but the PID of the video / audio ES can be arbitrarily specified by the broadcasting station.

  The tuner stability checking means 102 checks the “sync byte” and “transport error indicator” of the TS packet acquired from the tuner, and checks the number of normal packets and damaged packets.

  The stream configuration checking means 103 checks the PIDs of normal packets acquired from the tuner for a certain period and checks the ratio. From this ratio and the number of normal packets acquired from the tuner stability checking means 102, the bit rate of packets for each PID can be estimated. The PID of the video ES is estimated from the bit rate for each PID and the bit array indicating the ES.

  The stream cache control unit 104 determines when and which packet is stored in the stream cache memory by the tuner stability check unit 102 described above, and when the corresponding packet is acquired at the corresponding time, the packet is stored in the stream cache. Transfer to the memory 105. FIG. 4 shows the relationship between the type of packet stored in the stream cache memory and the time when this processing is performed.

  Until the tuner is stabilized, the stream cache control means estimates the PMT using the PAT search, the bit arrangement, and the bit rate for each PID described above, and stores the PMT in the stream cache memory. During this time, other packets are not acquired. A flowchart of the stream cache control means is shown in FIG. There are four types according to the acquisition and timing of channel selection information such as PAT and PMT. The relationship of acquisition of PAT and PMT is shown in Figs.

  (1) If the PAT and PMT are acquired (203,204) before the tuner setting is completed (200) and stabilized (202), the stream cache control means decides the PID of the video from those information, and adjusts the tuner. The corresponding packet is taken out from the packets sent from (205) and transferred to the decoder. Accordingly, in this case, the video packet is not stored in the stream cache memory. Decoding is started (206), and when normal video is created, muting is canceled (217). FIG. 6 shows the relationship between the tuner, stream cache control, and acquired data.

  (2) If the PAT is acquired (203) but the PMT cannot be acquired (204) before the tuner is stabilized (202), the stream cache control means estimates the PID of the video by the method described above (207 And the packet is stored in the stream cache memory. The PMT including the PID of the video is acquired from the PMT indicated by the PAT (210). If the estimated PID is equal to the PID of the video indicated by the PMT (211), decoding is started using the packet acquired from the tuner or the video packet stored in the stream cache memory (212). When normal video is created, mute is canceled (217). FIG. 7 shows the relationship between the tuner, stream cache control, and acquired data.

  (3) When the PAT cannot be acquired before the tuner stabilizes (202) (203), the stream cache control means estimates (208) the video PID using the method described above, and stores it in the stream cache memory. Save the packet. If PAT is acquired before PMT while saving video packets (209), and then PMT including the PID of the video indicated by PAT is acquired (210), the PID estimated as the PID of the video indicated by the PMT is If they are equal (211), decoding is started using a packet acquired from the tuner or a video packet stored in the memory (212). When normal video is created, mute is canceled (217). FIG. 8 shows the relationship between the tuner, stream cache control, and acquired data.

  (4) If the PAT cannot be obtained (203) until the tuner stabilizes (202), the stream cache control means estimates (208) the PID of the video using the method described above and stores it in the stream cache memory. Save the packet. If the PMT including the PID of the stored video ES is acquired before acquiring the PAT while saving the video packet (213), the packet acquired from the tuner or the video packet stored in the memory is used. Decoding is started (214). PAT is acquired (215), and when the estimated PMT is correct (216) and a normal video is created, mute is canceled (217). The relationship between the tuner, stream cache control, and acquired data is shown in FIG.

  Other than the above, information and video necessary for channel selection are acquired from the tuner (218).

  The stream cache memory 105 sequentially stores the received TS packets in the data area as shown in FIG. When saving to the stream cache memory, the type (301) and number (302) of packets received for each PID (300), the order of reception (303), etc. are recorded in the management area. When the stream cache control means 104 reads a necessary TS packet, it refers to the acquisition order (303) recorded for each PID and transfers the TS packet with that number.

  The Audio / Video decoder 106 decodes the received video / audio ES.

  When a normal video can be created, the mute canceling means 107 cancels the video mute.

  With the above operation, the tuner stability checking means 102, the stream configuration checking means 103, and the stream cache control means 104 acquire only TS packets necessary for an appropriate time, so that memory consumption can be suppressed. In addition, the information necessary for channel selection can be acquired using TS packets acquired in advance, and decoding can be started even if not all data can be acquired using them, thus shortening the channel selection time. It is possible to make it.

  As a second embodiment, a receiver for encrypted digital broadcasting such as terrestrial digital broadcasting, BS digital broadcasting, and pay broadcasting is provided. The block diagram of the digital broadcast receiving apparatus is the same as FIG. 2, but the flowchart is FIG. When the tuner settings are complete, search / acquisition of PAT starts. PMT and ECM are searched from the bit array and the ratio of PID and stored in the stream cache memory. There are five types according to the acquisition timing and timing of channel selection information such as PAT, PMT, and ECM.

  (1) The stream cache control means acquires (403) the PAT until the tuner completes the setting (400) and stabilizes (402), and acquires (404) the PMT including the video PID indicated by the PAT. If the common information (Entitlement Control Message; hereinafter referred to as ECM) including program information and control information necessary for decoding the video packet indicated by the PMT has been acquired (405), the video ES is acquired from the tuner (406). And transfer (407) to the decoder. Accordingly, in this case, the video packet is not stored in the stream cache memory. Decoding is started, and mute is released (423) when normal video is created. Figure 12 shows the relationship between the tuner, stream cache control, and acquired data.

  (2) The stream cache control means acquires the PAT and the corresponding PMT (403, 404) until the tuner is stabilized (402), but if the video ECM cannot be acquired (405), the video packet is Save (408) in the stream cache memory. When the corresponding ECM is acquired (409), the video ES acquired from the tuner and the video ES stored in the stream cache memory are decoded. If there is information necessary for starting video decoding processing such as aspect ratio in the decoded video ES, it is sent to the A / V decoder and decoding is started (410). When normal video is created, mute is canceled (423).

  (3) The stream cache control means has acquired PAT (403) until the tuner is stabilized (402), but if the PMT including video information has not been acquired (404), the video PID is The estimation is performed by the method described above, and the packet is stored (411) in the stream cache memory. Next, the PMT including the PID of the video is acquired (414) among the PMTs indicated by the PAT. If the estimated PID is equal to the PID of the video indicated by the PMT (415), the ECM indicated by the PMT is acquired from the stream cache memory or tuner and decoded (416) and sent to the A / V decoder to start decoding (417). To do. When normal video is created, mute is canceled (423).

  (4) If the stream cache control means cannot acquire (403) the PAT before the tuner is stabilized (402), the video PID is estimated by the method described above, and the packet is stored in the stream cache memory. Save (412). If PAT is acquired (413) first while saving the video packet, and then PMT including the video PID indicated by PAT is acquired (414), if the estimated PID is equal to the PID of the video indicated by the PMT (415) The corresponding ECM is acquired from the stream cache memory or tuner, and the video packet is decoded (416) and decoded (417). When normal video is created, mute is canceled (423).

  (5) If the stream cache control means cannot acquire (403) the PAT before the tuner is stabilized (402), the video PID is estimated by the method described above, and the packet is stored in the stream cache memory. Save (412). If the PMT indicating the PID of the video ES being saved is acquired (418) prior to the PAT acquisition (413) while saving the video packet, the ECM indicated by the PMT is acquired from the stream cache memory or tuner ( 419) and decode processing is started (420). The PMT is acquired (421), and the PMT of the PMT indicated by the PAT is the same as the PMT indicated by the PAT (422). When normal video is created, the mute is canceled (423).

  Other than the above, information and video necessary for channel selection are acquired from the tuner (424).

  The stream cache memory 105 sequentially stores the received TS packets in the data area as shown in FIG. When saving to the stream cache memory, the type (301) and number (302) of packets received for each PID (300), the order of reception (303), etc. are recorded in the management area. When the stream cache control means reads out the necessary TS packet, it refers to the acquisition order (303) recorded for each PID and transfers the TS packet of that number.

  The Audio / Video decoder 106 decodes the received video / audio packet. The mute release means 107 releases the mute when a normal picture can be created.

  With the above operation, the tuner stability checking means 102, the stream configuration checking means 103, and the stream cache control means 104 acquire only TS packets necessary for an appropriate time, so that memory consumption can be suppressed. In addition, the information necessary for channel selection can be acquired using TS packets acquired in advance, and decoding can be started even if not all data can be acquired using them, thus shortening the channel selection time. It is possible to make it.

  As a third embodiment, there is provided a digital broadcast receiver using a timer without using the tuner stability checking means as shown in FIG. Depending on the platform, it is difficult to obtain a packet other than a normal packet from the tuner, and it is difficult to implement the tuner stability check means. In that case, a period until the tuner is stabilized is set using the timer 108 in a pseudo manner, and the PID of the video ES is set using the stream composition unit 103 and the stream cache control unit 104 as in the first and second embodiments. Is estimated. In this way, necessary memory can be saved and high-speed channel selection can be realized.

It is a figure explaining the case where a tuner acquires PMT before PAT. It is a figure which shows the structural example of the digital broadcast receiver by this method. It is a figure which shows the structure of TS packet header. It is a figure which shows the relationship between the kind of packet preserve | saved in the memory for stream caches, and time. It is a figure which shows the processing flow of stream cache control. It is a figure explaining the state in case PAT and PMT are acquired before a tuner stabilizes. It is a figure explaining the state at the time of acquiring only PAT until a tuner becomes stable. It is a figure explaining the state at the time of acquiring PAT previously, while preserve | saving a packet. It is a figure explaining the state at the time of acquiring PMT including PID of an image first. It is a figure which shows the structure of the memory for stream caches. It is a figure which shows the processing flow of other stream cache control. It is a figure explaining the state in case PAT and PMT are acquired before other tuners become stable. It is a figure explaining the structural example using a timer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Tuner and demodulation part, 101 ... Packet separation means, 102 ... Tuner stability investigation means, 103 ... Stream structure investigation means, 104 ... Stream cache control means, 105 ... Stream cache Memory 106, video / audio decoder 107, mute release means 108, timer 300, TS packet identification number 301, TS packet type for each PID (PSI, ES ), 302... TS packet count for each PID, 303... TS packet acquisition order for each PID

Claims (6)

  A digital broadcast receiving apparatus, a data input means for inputting digital data including program identification information, a packet separation means for dividing and transferring the input digital data in units of transport stream packets, and the acquired transport stream packet Among them, a tuner stability investigation means for investigating the ratio of normal packets and damaged packets, a stream configuration investigation means for examining the bit rate for each PID in the transport stream, and a specific input obtained from the data input means. A stream cache memory for storing transport stream packets, a stream control means for determining which packet is acquired when the packet is acquired from the data input means, and transferring the packet to the stream cache memory or decoder; Information An A / V decoder that encodes and a mute control means that outputs the decoded information to the user, and the stream control means sets the video packet identification number from the ratio and bit rate even if the information necessary for channel selection is not acquired. A digital broadcast receiver characterized by estimating, determining when and which transport packet to store / output, and outputting to a decoder.   2. The digital broadcast receiving apparatus according to claim 1, wherein the stream control unit saves when and which transport stream packet to the stream cache memory based on information of the tuner stability check unit and the stream configuration check unit. 3. A digital broadcast receiving apparatus characterized by determining whether to read and transfer to a decoder and transferring the packet.   2. The digital broadcast receiving apparatus according to claim 1, wherein the stream cache memory is divided into a management area and a data area, and the acquired order is recorded in the management area for each identification number of the transport stream packet. A digital broadcast receiver characterized in that transport packets are recorded in the order obtained in the area.   A digital broadcast receiving apparatus, a data input means for inputting digital data including program identification information, a packet separation means for dividing and transferring the input digital data in units of transport stream packets, and measuring a certain time Obtained from the time measurement means, the stream configuration investigation means for examining the bit rate for each PID in the transport stream, the stream cache memory for storing the specific transport stream packet obtained from the data input means, and the data input means Stream control means for determining which packet is to be acquired and when it is transferred to the above stream cache memory and decoder, A / V decoder for decoding video information, and outputting the decoded information to the user Have mute control means to The stream control means estimates the identification number of the video packet from the time measuring means and the bit rate even if the information necessary for channel selection is not acquired, and further determines when and which transport packet is stored / output, and the decoder A digital broadcast receiver characterized in that the digital broadcast is output.   5. The digital broadcast receiving apparatus according to claim 4, wherein the stream control means stores when and which transport stream packets in the stream cache memory based on information of the tuner stability investigation means and the stream configuration investigation means. A digital broadcast receiving apparatus characterized by determining whether to read and transfer to a decoder and transferring the packet.   5. The digital broadcast receiving apparatus according to claim 4, wherein the stream cache memory is divided into a management area and a data area, and the acquired order is recorded in the management area for each identification number of the transport stream packet. A digital broadcast receiver characterized in that transport packets are recorded in the order obtained in the area.

Images